Telephone-exchange apparatus and system.



L ERICKSUN.

TELEPHONBEXCHANGE APPARATUS AND SYSTEM.y APPLlcArloN man mule. usos.Renewal) um. 2,|91a.

Patented Aug# 6, 1918.,

3 SHEETS-SHEET l.

1. ERICKSON.

TELEPHONE EXCHANGE APPARATUS AN'D SYSTEM. APPLICATION HLEDJuLYls, 190s.REnEwEu MN. 2,1918.

PatentedAug. 6, 1918.V

3 SHEETS-SHEET 2.

M ff 22e/7%! J. ERICKSON.

TELEPHONE EXCHANGE APPARATUS AND SYSTEM.

APPLICATION F|LEn1u|v1s.|soe. RENEwED JAN. 2. |918.

1,275, 1 4 1 Patented Aug. 6, 1918.`

Lide? am /Wweya. l

UNITED sTATEs PATENT oEFIoE.

JoHN Emerson, oEeHIcAeo ILLINOIS, AssIcNoR, BY MESNE ASSIGNMENTS, To

-. AUTOMATIC ELECTRIC co., A coaroaA'rIoN or ILLINOIS.

TELEPHOE-EXCHANGE APPARATUS AND SYSTEM.

Speclcation of Letters Patent.

Patented Aug. 6, 1918.

Application Med July 16, 190, Serial Nb. 326,450. Renewed January 2,191B. Serial No. 210,070.

To all whom it may concern:

` Special o improved construction and arrangement Be it known that I,JOHN ERICKSON, a

'citizen of the United States of America,

and resident of Chicago, Cook county, Illinois, have invented a certainnew anduseful Improvement in Telephone-Exchan Apparatus and Systems', ofwhich the illowin is a specification.

y invention relates to telephone systems in' general, but moreparticularl' to automatic or semi-automatic telephone exchange systems,and especially to systems in which electrically-'propelled andstep-by-step-actuated switching machinery is employed 'at the exchangeo'r central station, and adapt` ed to respond to electrical im lsestransmitted 'o'ver the telephone lines rom the subscribers substatio'fs.

For example, my invention is applicable to automatic telephone exchangesystems of that particular type in which automatic selectors andconnectors are employed at the exchange or central station, and in whichthe subscribers stations are equipped with electrical impulsetransmitters or calling devices for' controlling tlieoperations of thesaid selectors and connectors, thusmaking it possible for any' callingsubscribcr to first cntrol and operate one or more selectors for the purose ofi trunking through the exchange to t e' group of connectors atwhich the' called subscribers line terminates, and

to' finally control' and operate. a connector furthe pi'irpse ofcompleting the desired connection directly with the called subscribersline. In such a system the said selec' tors and connectors areai'i'tomatically'rcstored to ,nornial condition by thlihanging' .up ofone bf the subscribers telephones, as,

for example, by restoration ofthe calling sub'scribers receiver to theusual switchh'ook. It will also bc understood that Iin such a systemprovision is made for producing Aan audi lc call-signal at thesubstation of .any cal ed subscriber. l

Generallystated the object of my invention is the provision of animproved and highly eicient. tele hone exchange system.

Ejects` are lthe provision of an whereby the electrical impulsesnecessary foi operating `one or more automatic switches will nottraverse the entire line circuit between such switches and the callingsubscriber, but will only travela portion of such distance, aso-calledrepeater then being relied upon to duplicate or repeat such impulses inthe balance'of `the circuit extending to the switch or switches, thisarrangement being particularly advantageous and` nected sections of aline circuit extending between calling and called subscribers lines; theprovision of an improved construction and arrangement for enabling acalling subscriber of one automatic exchange to complete connection withthe line of a called subscriber of another automatic exchange, and tothen, aftericonversation is terminated between the two subscribers,automatically release all automatic switches, such as individualswitches, selectors and connectors, that may have been brought into usefor establishin and retaining thcdesired connectio'n be Ween the twosubscribers lines; the provision of a-trunk line which is normally openat a point between .its two ends, and 'which is provided with a repeateradapted to close the said normally open gap therein, as well as withmeans for dividing the' trunk line into two inductivelyconncctedscctions, and for repeating both 'voice currents andswitch-operating electrical impulses from vone to the other of the twoinductively connected trunk sections; and the provision of certaindetails andfeatures of improvement and novel combinations tendin'g toAincrease the general efiiciency andV improve the service o a telephoneexchange system ofthis particular character.

To the foregoing and other useful ends,

i approved type.

to the called line, a connector-switch F and a second-selector G.

Fig. 1 represents the apparatus at one central oice #1,- and- Fig. 2represents the apparatus at a second central oice which will bedesignated'as central 'oilice #2.'

Fi s.'1 and2 taken together represent an estab ished connection betweenthe'l subscribers A and D, em bodying the principles and features ofmyinvention.

It will be noticed that the apparatus is shown in an operative conditionmaintaining the connectionI between the two substations.

Each central'oiiice has its own battery; the central office #lhaving itsbattery B1 with its positive terminal preferably grounded at G1, and thecentralo ce #2 having its bat.- tery B2 with its positive terminalpreferably grounded at G2. These batteries may be of any suitablevoltage but good results are obtained when they are built to give apressure of from to 55 volts.

Fig. 3 'is a side elevation of the repeaterswitch.

Fig. 4 is a' front elevation of Fig. 3 with a section through the line4-4 removed.

The substation may be of any suitable or The substation shown in Fig. 1is, as usual, provided with a receiver 2, transmitter 3, ringer 4,induction-coil 5, switch-hook', imv ulse wheel 7. cam latch 8 (fornormally loc ing the dial),'a cam dog 9 andabattery 10. The impulsewheel 7 is, ofcourse, provided with a set of vertical impulse teeth 11and a rotary impulse tooth 12 for operating, 1 'esp`ectively, thelvertical impulse finger 14. and the rotary impulse finger 13 wit-hvrespect tothe ground post 15. The substation lground G3 is permanentlyconvnected to the ground spring 16, which latter is held normally away.from the ground spring by the insulating tip 18 upon the end ofthencafm latch 8,.said insulating tip normally resting upon the bentangled terminal of the ground spring 16, as shown at substation l), Fig.2. It will be understood, of

courseg'that in the subscribers dial (which is not shown, but which maybe of vany suit.

able or approved type), the impulse wheel 7 and the cam dog 9 are allrigidly secured Ito .the shaft 19. While the receiver is on theswitch-hook the switch-hook cam-arm 20 reniovfes'the ground spring 16from the insulating tip 18l so that the cam latch falls'in front of thepin 21 on the end of the ca m dog '9, whereby it becomes impossible torotate the dial. When the receiver is removed, however, the switch-hookis raisedby a suitable spring (not shown) and the cam-arm 20 by engagingthe face 22 of the cam latch 8 raises the latter sufficiently to permitthe pin .21to pass under the cam latch when the dial issuflicientlyrotated. It will be understood,

- however, that the ground spring 16, when the the pin 21 slides beneaththe said rounded sectionand raises the cam latch 8 a trile` more, sothat the insulating tip 18 may now ,leave the ground spring 16,permitting the latter to .engage the round spring 17 and thus establishconnectlon between groundGr3 and the ground post 15. When the receiver'AI is on the hook the cam 23 engages the spring 24 and thereby closes theringer 4 across the line. By depressing the sprlng 24 the said cam-arm23 not only closes the substation ringing circuit, but also byseparating the Springs 25 and' 26, opens the primary circuit, and byseparating the springs 27 and 28 opens the secondary circuit forremoving the. receiver 2 from across the line. When the switch-hook isup, the primary circuit is clofsed, and the second arycircuit comprisingthe receiver 2 is `bridged across the line. However, While the dial. isbeing operated and, therefore, -While the cam 29 of thecani dog 9 is outof normal position, the secondary circuit is openedup at the pointbetween the springs 27 and 28^so that no electric imtlie subscribersline conductors individually shall pass through the receiver to theother Side of the line. The switch-hook cam 30 is provided forcontrolling the release-springs 31,. 32 and 33, which release-springsare pressed inte` contact, grounding the subi scribers line conductorssimultaneously when` ,it becomes desirableto release the central offceswitching ap aratus. vThe signaling b utton 34 has the nction ofcontrolling the' spring 35 that normally rests in engagement with thecontactoint 36, but from which it 'is separated an carried intoengagement with the ground contact37,=whereby =only the Vertical side ofthe subscribers line may be grounded when he signals. With thisupparatus, the subscriber, when he .wishes to make a call,l removes hisreceiver'fpinthe izof substation ground Grx and ground post-15,

and the secondary circuit is opened-between the springs and 28 at theforward.mc tion of the dial. l At' the return motion of 100 pulses thatmay be delivered to either of digit, th'en the rotary si'de of the lineis grounded once and then the secondary circuit is again closed. Eachsucceeding operation' of the dial accomplishesthe same resultaccomplished b'y the second operation of the dial. The number havingbeen called the signaling' button `34 is pressed, whereby the secondarycircuit. Vis opened between the spring arid contact point 36, and thevertlcal side of the line is grounded when the spring-35 engages thecontact point 37. YIl? the ca lied subscriber is not busy the pressingof the signaling button rin gs the called subscr'ilbers substation bell,but. if he is busy a lm'sy signal will be' sent back to the calling'subscriber.V When a subscriber is through he then", by hanging up hisreceiver, presses the release-Springs 31, 32 and 33' into contact for amoment, grounds the telephone line conductors simultaneouslyror amoment, andthus restores all the switching apparatus `tl'r'ztthas beenbrought ifntoservice by him.

The' first-selector may' be off any suitable or approved type, such as'the selector shown in Patent'Nol 831,875. The subscribers verticl n'drotary line conductors' 38 and 39 terminate, respectively, in thevertical and r'otary line relays 40 and 4,1. The side switch wipers 42`and 48 are. respectively, connected with the line conductors 38 and 39,the former'` Wiper being normally in engagement with the contact point44 and thel latter wiper with the c'ontact point 45; The side "itch, asvis well known, conrri'bris'esbesides4 4thesidt-e switchwipers 42 and 43'the private Side switch wiper 46, the lrotary magnet side switch wiper47, and the lvertical magnet sidc' switch Wiper 47. The side switch i's'controlled by the .private magnet 48, and in.

the normal' or first position of the side Switch the side switch wipers42, 43, 46, 47 and- 47' engage, respectively, with the Contact points44,- 45, 57, 50 and 58'; in ther second position they rest onjthecontact points third poand 54', respectively; and' in the i sitfion in'engagement vwiththe Contact pointsV 4 i 56, 49, 58 and 50` respectively.

y v Through the medium ofthe vertical liner'elay 40, the subscriber'controls the vertical magnet 59,

which latter opera tes vertically the switchi shaft' (not shown). that'carries the line wipers 6U and. 61 and the rivat'e wil r` 62.y

lay 41, the subscriber contro-ls the'private magnet 48 and, therefore,the side switch. When the side switch is in second position the rotarymagnet 63 is energized and the switch-shaft that. carries the Wipers 60,6l and 62 is operated in a rotaryfdirection. The vertical and rotaryline relays-40 and 4,1 provide the mea-ns by which the releasemagnet l64is controlled by the subscriber.

The switch-shaft of the selector Bcarries a lso-called normal post arm65 which, when the shaft is out of normal position, permits the springr66 to engage thecoutact pointl 67 andthereby close a connection throughthe off-normal lamp 68. Theiprivate normal' conductor 69 leads to theconnector private banlr and by way of said private normal conductor thebridge-cut-o-relay 68 is energized whenever any subscriber'calls thesubstation A. The saidbridge-cut-olf-relay `rontrols the connectionbetween the vertical and rotary line relaysr40 and 4l and the bat' teryB1. It is necessary to thus disconnect said relays from battery becauseotherwise the ringing current finds a path through the said relays,`thus causingr some danger of in'- terference. Also, it is desirable toremovev the bridge 'from across the line that is formed through the linerelays 40 and 41 in series.

The repeater' (l, like the selector B, is provided with ,a vertical linerelay 69 'and-a rot-ary line relay 7 0` through themedium of which theVsaid repeater is controlled The Said repeater is .provided with a shaft71 which carries a pair of wipers 72 and 73 and which is operated by arotary magnet'74. The shaft carries two sets of longitudinal teeth 75and 76, the former adapted to be normally engaged by a rotary pawl 77;The rotary magnet 74 is provided with an, armature 78 which is providedwith anv arm 79 upon the end of which the paw-l 77 is ivotally mounted.A retracti-ng-spring 8- is i adapted always to maintain atension ongthepawl 7 7 in' the direction of the longitudinal teeth 75. A suitableadjustable stop 81,.Fig.

3,1 is mounted upon a cross member 82 that is secured to the post 83.Thesaid stop limyits the strokeof the armature7 8 toward theV core ofthe magnet 74. Another'stop 84-also mounted upon the cross member 82limits the motion of the armature 78 i-n the opposite direction; Thesaid arm 79 controls a copple'of springs 8i and 86, the former" ofwghich may be of heavy spring material and :tnswers as a rctractingz`force for restoring the armature 79m normal condition, Vand for rotatingthe shaft 71 at the same time'.`, It

will be noticed' that there are onlyenoifrgh longitudinal 4teeth 75 forrotating 'the' shaft 7T four steps. lt is not abs6lutely necessary thatthere should be four, asitheslmft may be arranged to be providedwithfiinly three ori two or any suitable number, de riding upon thesize' of the exchange and t e nmisis4 ber of digits in the number to besecured by the repeater. yIt should be understood that by adjusting thestop 98 relatively to the stop pin"97, the number of steps necessarycause the wipers 72 and 73 to engage their corresponding bank contactsmay be readily changed. In the illustration in Fig. 1, it is onlynecessary to advance the shaft three steps to carry the wipers 72 and 73into engagement with the lcontacts 92 and 93, respectively. At each`step of the shaft 71 the latter is retained by a ratchet 87 upon thearmature 88 that is controlled by a -ratchet magnet 89. The spring 91maintains the ratchet 87 in engagement with the longitudinial teeth 76.When the subscriber starts to release, the rotary magnet 74 and theysince the shaft is maintained in a normal position determined by theadjustment of the pin 97 located on the upper side of the shaft,4 and astop member 98. The norinal position of the shaft is s uch that it takesthree steps to carry the wipers into enga e.

ment with the bank contacts 92 and 93. e.

normal'position of the wipers is shown lin Fig. 1 bythe lines athesecond position by b, the third position by c, and the fourth positionby the .bank contacts themselves. When the. repeater is located 1n thecircuit, as shown in Fig. 1, and usedv as a terminal to a ytrunk lineleading to another exchange the local trunk conductors that connect therepeater C with the pro er firstlselector bank contacts terminate in t ewipers 72 and v7 3, and t e trunk conductors 99 and 100 that lead to t eother exchange terminate in the condensers 101 and 102, respectively, orin any` other suitable inductive apparatus. The repeater as a whole isbuilt upoiral suitable base 103, the mechanism itsel being assembledupon a frame 104 that is attached to the base 103 by means of bolts 105.Between the base 103 and the frame 104 the condensers 101 and 102 areheld in position in any suitable manner. The base is provided with aslot 106 on the upper side and another slot 107 on the under side,through which slots screws are passed to secure the switch to a iframeor board in any suitable locality. The switch-shaft 71 is retained innormal position' by any suitable means, such as the coilspring 108 thatis inclosed within the casingv 109, Fig. 3. The line-relays 69 and 70control the springs 110, 111, 112, 113 and 114 which are included incertain circuits to be hereinafter described. In a system in which.Wiper 124.

controlled by the calling subscriber through Y vsecond-selector for sucha relay as the `bri(igecut-ofrela 68 of the first-selector B and it is,there ore, omitted and the vertical and rotary line relays 117 and 118|,respectively, are connected directly to the battery. There is also nouse for a private normal conductor such as the private normalconductor'69, and thespring 119 controlled by the normal post arm 120 isconnected through an oli-normal lamp 121 for 'indieating when thesecond-selector is oli normal. Whenever the switch-shaft is raised thenormal ost arm 120 clears the spring 119, which atter then passes intocontact with .the grounded contact just above 'it and thus establishesanvenergizing circuit through the lamp' 121 from ground to the battery.

l The connector switch F may also be of any suitable or a' proved type,such as the connector descri ed in Patent No. 815,176. The mechanicaldetails of the selector and connectorare, as is'well known, very muchthe same, altho h there is some material difference in t e circuits. Theconnectorswitch shaft, like the shaft of. the selector, and-which is notshown, carries the usual line wipers 122 and 123 and the private Theconnector-switch- -isy also the medium of the vertical and rotary linerelays 124 and 125. The vertical line relay 124 directl controls thevertical magnet 126 and also tli'e rotary magnet 127. The oice of thesaid vertical magnet 126 is to give the shaft and the shaft wipers theirvertical movement, and the rotary magnet 127 imparts to the said shaft arota or circular movement. The lrotary line re ay controls the privatemagnet 128, which latter under certain conditions controls in turn thevertical and rotary magnets 126 and 127 and the release-magnet 129, andalso the side switch wipers 130, 131, 132 and 133, all of which areshown. The said side switch, like the side switch of the first-selector,has a normal-or first osition, a 'second position and a third position.In normal position the respective side switch wipers engage the contactpoints 134, 135, 136 and 137 g in second position the contact points138, 139, 140 and 141, and in the third position the contact points.11i-2,1143, 14A: and 145. The release- Inagnet 129 is also controlled bythe line relays 124 and 125 conjointly, and by the back-bridge-relays146 and 147 conjointly. Like the repeater the connector divides thecircuit that passes through it into two sections by thev use of thecondenser-s 1118 and 149. The connector has in addition a ringer relay150 b means of which the ringer generator 151 1s bridged across theterminals of the called line to signal the called subscriber. Eachexchange also has a busy signaling apparatus H of any suitable design,as for example an interruptor 152 in series with a seconda-ry Winding153 of an induction-coil 154',

` whereby a busy signaling. current is induced as is well'known,

in the primary Winding- 155 of thev said induction-coil 154. Saidprimary winding 155 is connected to the contact point 156 against which`the switch shaft spring 157 is allowed to press when the normal postarm 158 is raised.

'lhe first-selector E of the called line is the same as thefirst-'selector B and needs, therefore, no description. The substation Dis also the same as substation A.

The connection bet-Ween the two exchanges may be made in any convenientmanner and l do not confine myselt to any particular arrangement, sincethe system herein disclosed is variable. Iii' it is assumed that themaximum number of subscribers to be accolnmodated at each exchange is`ve thousand-then the rst five levels of the firstv selectors ofexchange:#1 may be devoted to local connections, and the last live levels totrunk 4connections to' exchange #2, each of which trunk connections, .ofcourse, comprising a repeater similar to the repeater C. The reversewould b'e the arrangement for exchange #2, as in thatV exchange thefirst five levels would be devoted to trunk operations to exchange #land thel last five levels to local connections. Ii do not limitV myselfto this arrangement even w-henlthe maximum numberto be accommodated ateach exchange is not to exceed-'five hundred: It will also beunderstood, of course, that all of the switches may be arranged ingroups. For example, the first-selectors of the same Vgroup havev allsimilar bank contacts connected in multiple. If each group consists ofone hundred first-selectors there will be one hundred banks. Therefore,if any one of the selectors of a given hundred connect with the repeaterC a guarding potential will be established at the contact engaged by theprivate Wiper 62, and at all other private bank contacts inmultiple, sothat'all' other selectors of that group, if .they make a call, will passover the trunk that leads to the repeater@ without interferingI with theconnection. The same grouping arrangement,

appl-ies to the central oticc #2 as well, and to all the switches.

bridge-cut-oE-relay springs 166,159 an The operation in detail is asfollows: To call the number 2220 the subscriber at substation A, aspreviously described,opera`.tes

the dial once for each digit. The first operation of the dial resultsinthe vertical line conductor 38 being grounded twice, and as a furtherresult the vertical linerelay 40 of the first-selector D is energizedtwice, the current flowing in each case from ground G3 through theground springs 16 and 17 to the ground pos t.15s thence through thevertical impulse finger 14:A to the vertical line conductor 38, verticalline relay L10, bridgecu't-oE-relay springs 159 and 16() to the batterylead`161 and from battery Bl? to ground Gr. Each time that the verticalline relay 10 is energized the line relay springs 1 62 and 163 arepressed into contact and an energizing circuit is thereby establishedthrough the vertical magnet 59. Current throu h the said magnet flowsfrom ground through the springs 163 and 162, private springs 164 and165, side switch wiper 47', Contact point 58', vertical magnet 59 to thebattery lead 1611 and through battery B1 tc ground G1. The verticalmagnet 59 then operates to raise the shaft forV placing the wipers 60,61and 62 opposite the level oontaining the contact points at which thetrunk line conductors that leadl to the repeater C terminate. When the.rotary line conductor 39 is grounded the rotary line relay 41 isenergized in turn. The current throu h said. relay lows through groundG3 to t e ground post 15, then through the rotary impulse linger 13 tothe rotary line conductor 39a hence'throughthe rotary line rela 41,

to the battery lead 161 ,thence through battery B'1 to ground G1. Therotary line relay in turn magneti-zes the private magnet L18 byestablishing a circuit through/ the line relay springs 167 and 163. Thecurrent for energlzing the private magnet flows from ground G throughthe line relay springs 163 16'7 to the private magnetflS, thence throughbattery lead 161 and through battery B1 to ground G1. The private magnet4S then operates to release the side switchfrom first to second'position, and as a result. a circuit is closed through the rotary magnetlo o 63 when the side switch wiper '4:7 engages thev con-tract point 54.The current through the rotary magnet flows from ground Gr's to thecontact point 54, thence through the side s\v,i'tch wiper 47, one coilof rotary' magnet 63, interruptor springs 168 and 169, another coil'ofrotary magnet 63 to tht battery lead 161, thence through battery B1 Therotary magnet is energized step by step and the wipers 60, 61 and 62 areadvanced in like mannerover bus contact points'until the wipers nd,therst idle trunk line which, it is aumed, is the trunk line that leadsto the repeater C. As long as-,the

to ground. G.

- considered in due time.

private Wiper 62 is passing over busy con tact points the private magnet48 is retained energized and the side switch is locked in secondposition, as is well known, until all guarded points are passed. Thecurrent through the private magnet, while the private Wiper 62 is passinover busy contacts, flows from the groun ed terminal G1 of the batteryB1 through the occupying switch to the private wiper 62, thence throughthe side switch wiper 46, contact point 53, private magnet 48 to thebattery lead 161, thence through battery B1 to ground G1. At the instantthat the private magnet 48 denergizes, after the private wiper passesover busy contacts, the side switch 'is tripped into third position, orif there are no busy contacts to be passed over, the rotary ma net 63,as is well known, trips the side switc to third position with the resultthat as soon as the side switch wipers 42 and 43 engage the contactpoints and 56, respectively, the subscribers line conductors 38 and 39are extended to the repeater C. Also, since the side vswitch wiper 46 atthe same time engages the contact point 49 a guarding potential isestablished at the private wiper 62 to protect the seized trunk linethat leads from the repeater C from being molested by any otherswitch.The second operation of the dial, since the line is now extended, isdirected to the re-A peater C. Grounding the vertical line conductor 38twice energizes the vertical line relay 69 twice, the' current in thiscase flowing from ground G3 to the ground post 15, thence through thevertical impulse finger 14 to the vertical line conductor 38, sideswitch wiper 42 of the selector B, vertical. line wiper 60, verticalline relay 69 of the repeater C to the battery lead 161 and throughbattery B1 to ground G1. Each time that the said vertical line relay 69Tis energized the springs 110, 111 and 112 are pressed into Contact. Thespring 110 connects through the ratchet magnet 89 to the spring 85, atwhich spring the circuit is open, so that the operation of the spring110 at this time is not of any consequence,'but the closure of contactbetween the springs 111 and 112 rounds the vertical trunk conductor 99.I his, of course, occurs each time that the vertical line relay 69 isoperated, Grounding the vertical trunk conductorV 99 in turn operatesthe switches at the exchange #2, which operation will be scriber groundsthe rotary line condhctorl 39 he energizes the rotary line relay 70 ofline relay 70 to thebattery lead 161, thence through'battery B1 toground G1. The op- When the subs eration of the rotary line relaycauses' the line relay springs 114, 113 and 112 to be pressed together-The closure of the contact between the springs 113 and 112 sends aground impulse to the rotary trunk con-- ductor 100 for operating theswitches at the second exchange and the eiiect of thus grounding ytherotary trunk conductor will be considered hereinafter. The establishmentof connection between the springs 114 and 112, through the interveningspring 113, energizes the rotary magnet 74 of the repeater C. Thecurrent passes from ground Gx through the springs 112, 113 and 114 tothe rotary magnet 74 to the battery lead 161, thence through battery B1to ground G1.

VThe rotary magnet 74 upon energizing attracts its armature 78 and thusdisengages the pawl 77 from the teeth 75 and closes contact betweensprings 85 and 86. Upon the denergization of magnet 74 armature 78 ispushed back by the spring 85 and pawl 77 rotates the shaft 71 one step;but just at this stage of the call such operation has no effect. Thevertical trunk conductor 99 terminates in the vertical line relay 117 ofthe second-selector G and the rotary trunk conductor 100 terminates inthe ro-v tary line relay 118 of the said selector. Connected to saidconductors, respectively are also the side switch wipers 171 and 172.Therefore, grounding the vertical trunk conductor 99 twice, as de#scribed in the preceding, operates the -vertical line relay 117, thecurrent flowing from ground G6 at the repeater C through the line relaysprings 112 and 111 to the vertical trunk conductor 99, thence throughthe vertical line relay 117 to the battery lead 174 and through batteryB2 to ground G2. The vertical line relay 117 in turn operates thevertical magnet 175, as described in connection with. the first-selectorB, so that the shaft wipers 176, 177 and 178 are raised to the levelwith the contacts from which a trunk .line leads to the connector F. yAs

soon as the switch-shaft rises the normal post arm 120 permits theswitch shaft spring 118, which latter in turn energizes the pri- A `vatemagnet 180 for a moment and permits the sidel switch to escape fromfirst to second position. The current through the said 'rotary linerelay 118 flows from ground G.

at the repeater C through the springs 112 and 113 to the rotary trunkconductor 100, through the rotary line relay 118 to the battery lead174. and through battery B2 to ground G2. As soon as the side switchwiper 181 engages the contact point 182 an energizing circuit isestablished through the maaier rotary i'nagiiet 183, which latteroperates to rotate the-shaft in the saine manuel.' that the rotarymagnet oil the first-selector B op crates. The current through therotary magnet 183 flows 'from ground G7 through the side switch Wiper18l, rotary i'nagiiet 183 and its allotted iiiteii'upter springs to thebattery lead 17 1, and through battery B2 to ground G2. 1VJheii therotary i'nagnet operates, the side switch is then tripped into -thirdposition, or if the wipers are carried over busy contacts the sideswitch does not pass to third position until the private mag* net 180denergizes. As soon as the side switch passes to third position the sideswitch Wipers 171 and 172 upon engaging the contact points 184l and 185,respectively, extend the trunk line conductors 99 and 100 to theconnector F at the same time that the side switch wiper 186 engages theContact point 187 and a guarding potential is established at the privateWiper 178 for preventing other switches 'from establishing coiiiiec tinwith the connector l?. The third operation of the dial, since thesubscribe-Ns line conductors are extended to the con nec-tor F, isdirected to the repeater for the purpose of operating said connector.When the vertical line conductor 38 vis grounded twice the vertical linerelay 69 oli' the repeater C is again operated twice, whereby thevertical trunk conductor 99 is again grounded twice. Grounding thevertical trunk conductor 99 energizes the vertical line relay 124 of theconnector. rlhe current through said relay flows from ground G6 to theVertical trunk conductor 99, thence through the side switch wiper 171.,Contact point 184, Vertical line wiper 176 to the vertical line relay124, thence to the battery lead 174 and from battery B2 to ground G2.The vertical line relay 124 i'n turn presses the line relay springs 1,88.and 189 into contactY andV as a result the magnet `126 is operated..The current through Isaid mag,

net .flows from ground Gs to the springs 189 and 188, private springs19() and 191,l side switch wiper 133, contact point 137 vertical imagnet 126 lto the battery lead 174: and

throughbattery B2 to. ground G2. They vertical magnet 126, as usual,operates 'to raise the switch-shaft. Being operated ltwice the shaft israised two steps and the` shaft wipers 122,123 land 124 are carried `toa level in which the line of the subscriber :#2220 is located. When therotary line conductor 39 is grounded once the'rotary line relay 70 ofthe repeater C is energized once as before,

and as a result the rotary magnet' 74 of the4 repeater C isagainoperated once and the shaft 71 rotated another step and the wipers 72and 73 carried .to a position marked by the-lines c.

ing the rotary line relay 125 of" the connector At. the same time therotary. trunk conductor L00 is grounded once, caus- F to be operated.'lie ciu-rent flows through the rotary relay 125 troni ground G to therotary trunk conductor 106, thence to the side switch 'wiper 17)J o'ltthe second selector G, Contact point 185, rotary line Wiper 177, rotaryline relay 125 to the battery lead 174;, thence through battery B2 toground G2. The rotary' line relay 125 in turn eiufrgiaes the privatemagnet 128 upon pressing the line relay springs 192 and 189 intoContact'. The current through said private magnet passes from ground G8through the springs 189 and 192, private magnet 128 tothe battery lead174-, thence through battery B2 to ground G2. The private magnet beingopen 'ated momentarily causes the side switch Ato vpass froinirst tosecond position. As a result the side switch. Wiper133 shifts intoengagement with the contact pointlll. substi tuting the rotary magnet127 for the vertical magnet 126, subjecting the former to the controloit' the vertical line relay 124.- The fourth operation of the dialcauses the rerticai line conductor to be grounded again, the verticalliiie relay 69 of the repeater C to be energized again. and thevertical.. trunk conductor 99 to be grounded again (each ten times),since the fourth digit is the-digit O. Each time that the vertical trunkcon ductor'99 is grounded the vertical line relay 124 of the connector Fis operated over circuits that have been pointed out, but instead or'operating in turn the Vertical magnet 126 it each time operates insteadthe rotary magnet 127. The circuit through the said rotary magnetextends from ground G8 to the side switch wiper 133, thence through thecontact point 1111 toi' the said rotary 1nagnet 127' and to the batterylead 174- and through battery B2 to ground G2. switch sha-tt is thusrotated step by step Luntil the Wipers 122, 123 and yA24-are carriedinto engagement with the normal conductors y 193, 19,4 and 195 thatreach to the irst-se ductors 193 and 194 extend to the called sub.n

The

scriber"s` line and lto the` substation #2220.

Grounding the rotary line conductor 39 for the last time energizes therotary line relay 70 ofv the repeater C, which latter in turn 115 93,respectively. V At the same time the rotary trunk conductor 100 isgrounded.- once. Grounding the rotary trunk conductor 100 energizes therotary line relay` of the connector F. the energization of whichreswitch, if the called line is busy,'or therelease of" the side switchfrom second to third position, if the lineis not busy, which latlaycauses either the release of theconnector 1245 ter operation placesthefside switch wipers y '130 and -131 in engagement with the contact13,0

points 142 and 143, thus placing the calling subscribers line inconnection with the called subscribers line through the 'condensers 148and 149. This connection is iharked by heavy lines in Figs. 1 and 2. Itwill be assumed, first, that the energization of the rotary line relay125 produces the latter result-that is, releases the connector sideswitch to third position. lt will be noticed that the callingsubscribei"s vertical line conductor 38 extends through the verticalside switch wiper 42 and the vertical line Wiper 60 of the lrstsclectorB to the vertical Wiper 72 of the repeater C, Which ,latter being now inengagement with the contact point 92 extends the circuit through thecondenser 101 to the vertical trunk conductor 99, thence through theside switch wiper 171 and vertical line Wiper 176 of the second-selectorG to the connector condenser 148, thence through the ringer relaysprings 190 and 197, side switch Wiper130 to the vertical line Wiper122, normal conductor 193, called subscribers vertical line conductor198 through the substation ringer 199 to the rotary line conductor 200and back to the rotary. normal conductor'194, line Wiper 123, -sideswitch wiper 131, ringer relay springs 201 and 202,'condcnser 149, linewiper 177, and side switch Wiper 172 of the second-selector G, rotarytrunk conductor 100` lcondenser 102, contact point 93 and rotary Wiper73 of the repeater (l, rotary line wiper 61 and side switch Wiper 43 ofthe first-selector B to the rotary .line conductor 39, thence throughthe receiver 2, secondary winding 203 of the induction-coil 5 back tothe vertical line conductor 38.

To signal the called subscriber the calling subscriber'presses hissignaling button 34, thereby grounding the vertical line'conductor 38over a. circuit that extends from ground G3 through the ground springs16 and 17, conductor 204, contact oint 37, spring 35 to the verticalline con uctor 38. As a result the vertical line relay 69 of therepeater C- is energized, which latter thenv grounds the vertical trunkconductor 99, causing in turn the energization of the vertical linerelay 124 of the connector F.

Said relay 124, since the side switch wiper 133 .is in third position,causes the ringer re-` lay 150 to become magnetized. The current throughsaid ringer relay flows from ground G8'. to the side switch wiper 133,thence through the ringer relay 150 to the battery lead 174` and throughbattery B2 to ground G2. The ringer relay upon attracting its armatureforces the ringer relay springs 201 and 197 onto the ringerrelay springs205 and 206, thus breaking the connection betweenthe calling subscriberand the called subscriber, and throwing the ringer generator 151 acrossthe called subscribers l1ne for ringing the bell 199 at the station ofthe latter. In ordeito prevent the ringing current from interfering withthe line relays 207 and 208 of the called first-'selector E thebridge-cut-of-relay 209 is energized as soon as the connector sideswitch Wiper 132 engages the grounded contact point 144. The circuitthrough said bridge-cutoi"-relay Hows from ground G9 through the sideswitch wiper 132 to the private Wiper 124', conductor 195, side switchWiper 210, con tactpoint 211, thence through to the bridgecutoff-relay209 to the battery lead 174 and through battery B2 to ground G2. Thesaid relay 209 upon energizing separates the springs 212, 213 and214,'thereby breakin thel connect-ion between the said relays 207 and208 and battery lead, and between each other, leaving the line clear atthe selector E. The saine circuit that connects the side switch Wiper132 With the connector private Wiper 124 is used for establishing aguarding potential that protects the seized line from interference bysome other subscriber. Busy lines are protected as describedL byguarding potentials.- The calling line is protected by guardingpotential established at the connector banks from the selector B of thecalling line and the called line Vis protected by a guarding potentialestablished by the connector. In either case if the line is busy,therefore, there is a guarding potential at the private bank contactthat corresponds to his number. Assume, for eX- ample, that the calledline #2220 is busy at the. time that the rotary line relay 125 of theconnectorF is energized. The said relay then presses the springs 219 and220 vinto contact. As a result the release-magnet 129 is placed inconnection with the private Wiper 124. which latter has been previouslyrotated onto a grounded contact. As a result there is s'ent a flow ofcurrent through the release-magnet 129 from the private Wiper 124 to theside switch wiper 132, which is 'now in second position, contact point140, springs 219 and 220, release-magnet 129 to the battery lead 174 andthrough battery B2 to ground G?. As a result the release-magnet becomesmagnetized and the` connector-switch is released and restored to ynormal condition. Then when the'subscriber presses his signaling buttonand grounds the vertical line conductor 38 he energizes the verticalline relay 69 at the repeater C, grounds the vertical trunk conductor 99and 'energizes'the vertical line relay 124 of the through theswitch-shaft springs 156 and 157, Side switch wiper 130, ringer relay:spr-ings 197 and 1915, condenser 148 to the Icalling subscribersvertical line conductor 138 over circuits that have been described,

through the receiver 2 back to the rotary line conductor 39, thence tothe rotary trunk conductor 100 and to the rotary line relay 125 ci theconnector to the battery lead 174 and back to thc busy coil 155. T he'calling subscriber upon, hearing the busy signal. releases hisswitching apparatus at, the central olice. It will be noticed thatduring the building up of the connection between the substation A andthe connector F the line relays 4-0 and 41 of the first-selector B andthe line relays 117 and 118 of the second-selector G are retained acrossthe line. It follows, therefore, that even after the selector Bestablishes connection with the repeater C the line re lays 40 and L11become energized, res ec tively, when the line conductors 38 an B9aregrounde'd. The energization of said relays is of no consequence,however, after the side switch passes to third position. Tho

'lso

same is true of the second selector G after the side switch ,passes tothirdV position. It will be shown, however, that in a bridging' systemthe said selectors B and G are dependent for their release upon theoperation of their line relays when the line conductors 38- and 39 aregrounded simultaneousl The release occurs when the calling sag scriberrestores his receiver -2 and thus presses the releasefsprings- 31, 32and 33 into contact, and thus simultaneously grounds' the vertical androtary line conductors 38 and 39 for a moment. Grounding the verticaland rotary line conductors 38 and 39 simultaneously energizes thevertical and rotary line -relays 69 and 7 G of the repeater C at thesame time, whereby all the springs 110, 111, 112, 113 and 1111 arepressed into contact. As a result the line relays L10 and 41 of the.selector B energize over known circuits at the Asame time. Also, the rotary magnet 74 is magnetized, the ratchet magnet 89 is inagnetized, andthe vertical and rotary trunk conductors 99 and are grou-ndedsimultaneously. The circuit through the rotary magnet 74 is known. Theenergizing circuitv through the ratchet magnet 89 extends from ground G6through the springs 112, 111 and 110 to the ratchet; magnet Bil-thencethrough the springs 85 and 86 to the battery lead 161 and throughbattery B1 to ground G1. Assoon as the rotary magnet 7 4 of the repeaterC and the ratchet magnet 89 Aattract their armatures together theswitchshaft 71 and Wipers and 73 are restored to normal condition by thetension ci. the retract-ing spring i955. The vertical and rotary trunkconductors 99 and 100 being grounded at the saine tima previouslystated, cause the ver li '1241y and 12s rt 4sult an energizing circuitis established throi'zgh the release-magnet 129 of the connector. Thisrelease circuit extends 'from ground GB at the connector F to thesprings 189 and 188, private springs 190 and 215 to thel springs 219 and220, release-magnet 129 to the battery lead 17 L1 and throughbattery l:to ground G2. The connector releasemagnet thus energizes, releasing theconnec torshaft and side switch at once, As soon as the subscribersrelease-springs 31, 32 and 33 'disengage the line relays 40 and 41 ofthe selector B denergize, releasing the selector B. Also, the linerelays 69 and 70 of the repeater C deenergize and as'a result the rotarymagnet 74 and the ratchet magnet 89' ot the repeater C denergize,leaving the repeater C fully restored and removing the ground connectionfrom the trunk conduc tors 99 and 100. The removal of the groundconnection from the trunk conductors 99 and 100 causes thedeenergiaation of the vertical and rotary relays 117 and 118 o1' theselector G and of the line relays 1.2/1 and 125 of the connector F. Assoon as the line relays 117 and 118 ot the selector (l deinergize, thesaid switch G becomes restored; also, the denergization of the linerelays 124 and 125 of the connector F leavethe said switch fully re;

y stored.

The called subscriber answers by removing his receiver 225, bridges hislsecondary circuit, including said receiver and thesecondary winding 226in series, across the called subscribers line.4 The subscribers thusIbecome connected over the heavily marked conductors, shown in Figs. 1and 2, which conductors have been pointed out. After they are throughcommunicating the calling subscriber may destroy the con'nec tion byhanging up his receiver 2. thus grounding the vertical and rotary lineconscribed, with the exception that in this case,

since -the switrlrshaft is rotated, the shaft iii-stiotates to normalposition and then-talle to its normal place. As soon as the shaft ot theconnector F is released from engagen ment with the trunk line" leadingto the called selector E the. private Wiper 124, 'breaks connection withthe private normal conductor 195, restoring as a result ythebricigarestaoifrelay 239 oi- 4the AA.einecistitor' E, whereby the linerelays 207 and 208 return to their normal condition under the control ofthe substation D. As soon as the release-springs 31, 32 and 33`separatethe ground connection to the conductors 38 and 39 is removed and as aresult the first-se lector B is restored, and the repeater C isrestored, which latter then removes the ground from the trunk conductors99 and 100, and as a result. permitting the selector G and connector Fto regain their full normal condition. If the called subscriber shoulddesire to use his selector E before the calling subscriber A restoresthe switches he must first ground his line conductors 200 and 198simultaneously by pressin the release-springs 227, 228 and 229 toget erafter the ground springs 230 and 231 have come into contact. As a resultan energizing circuit is established through the back-bridge relays 146and 147 ot' the connector F from ground G12 through the springs 230 and231 to the ground release-spring229, thence to the vertical lineconductor 198 by one path through the ringer relay springs 197 and 196,throughl the vertical baclebridge-relay 146 to the battery lead 174,thence through battery B2 to ground G2. Over another branch the currentpasses from ground release spring to the rotary line conductor 200,thence through the ringer relay springs 201 and 202- and through therotary back-bridgerelay 1l7 to the battery lead 1741', and fronr batteryB2 to ground G2. The said relays 146 and .147, upon energizingsimultaneously, force the springs 232 and 233 together and thusestablish a circuit from ground Gr13 through the said springs 232 and233 and through thel release-magnet 1.29 to the battery lead 174, andthence through battery B2 to ground (l2. The connector F is thenreleased, the wipers 122, 12,3 and 124 disconnected from thefirst-selector E, leaving the first-selector E and connector F fully restored. l'la ving been restored the selector 11i may be used by thesubscriber' at substation D. The calling subscriber may then, bygrounding his vertical line conductors 38 and 39, upon hanging up hisreceiver restore the remaining switcl'iesB, C and G in a manner that isalready known. It will be evident from the structure and description ofthe repeater C that the said switch is adapted to be inserted in anypart of the circuit between either the substation and the selector B, orbetween the second-selector G and connector F, or in any other position,for the repetition of impulses- The resistance'of the coils 69', 70, 74and 89 'may be ot any suitable character, but goed results are obtainedwhen the coils 69 and 70 are wound to five hundred ohms each, and thecoils 74 and 89 to sixty ohms each.

-Obviously with.. the use of my repeater the subscribers of two dierentexchanges, which may be a considerable distance apart, may easily obtainconnection with each other, notwithstanding the fact that the distancebetween the calling exchange and the apparatus of the exchange to whichthe called subscriber belongs may be so great that ordinarily/theresistance of the line would be too great to successfully operate,directly, the relays and magnets of the switches in the distantexchange. Under such conditions the repeater C acts as a re lay stationfor the switch-operating inipulses thatoriginate in the calling substa-\tion. It will be evident, then, that even where the exchanges are notso far apart the trunk conductors 99 and 100 may be made of materialwhich is of comparatively high resistance, suoli as iron, instead ofmaking it necessary to use copper for the trunk lines. In a system wherefor any reason it were desirable to have two repeaters, one after theother, vfor example, one at the end of the trunk line as shown in Fig.l., and one at the other end ofthe same trunk line, in place of thesecond-selector G, there is no reason why such an arrangement should notbev made. My repeater, it will be evident from its construction, isadapted to be thus arranged in the circuit. It is not even necessarythat the repeater should be used to transmit impulses from one eX-change to the other, but may be used to transmit impulses betweenswitches no matter where they may be located.

The hub of the repeater C that Carries the longitudinal teeth 75and 76may, if desired, be either riveted to the shaft or secured thereto bymeans of a screw or other device. The object in providing'a normallyopen circuit between the locall trunk cony ductors 234 and 235 whichconnect the repeater C with the banks of the selector B, and the trunkconductors 99 and 100, isto preclude the impulses which operate therelays 69 and 70 from discharging through the condensers 10'1 and 102and thus perhaps affecting the relays at the second-selector (l, beforethe relays 69 and 70 operate to ground the trunk conductors 99 and 100.

From the foregoing it will be seen that l provide a. pair of repeaterrelays, such as the relays 69 and 70, which are adapted to be used insuccessively cont-rolling a. selec tor and a connector. In other words,the second-selector G and the connector F are successively responsive tothe electrical ground impulses established in the trunkY line by theenergizing of the said repeater line relays. It will be seen that therepeaer C is individual to one end of a trunk line, while thesecond-selector G is individual to the other end of the same trunk line..By placing the said repeaters in the trunk lines it will be seen thatthe number of repeaters .tit

titi

need only be substantially ten per cent. of the total number ofsubscribers. The firstseleetor B, or other suitable individuahlineswitches, may be controlled directly by the -subseribers electricalimpulse transmitter oi' calling device, b ut after the first trunkselection is made the calling subscriber then controls thesecond-selector and connector through the medium of the repeater (1-that is to say, the calling subscriber simply operates the relays ofthe said iepeater, and these repeater relays then correspondingly groundthe trunk 'line at the other side of the condensers or other inductiveconnections by which the repeater divides the trunk line intoinductively connected sections. In this Way the distance between the twoexchanges-that is to say, the distance between the repeater C and thesecondselector (ir-can be considerably reduced, and at the saine time,notwithstanding the large amount of total resistance included in theline circuit between the second exchange and the calling subscriber, thenecessary switching operations will be performed with accuracy andcertainty at the second exchange. Oi course, as previously stated, lthel said repeater can bc employed for directly controlling and loperatingall automatic switchesy necessarily employed in establishing connectionbetween the calling .and called lines. Preferably, however, the saidrepeaters are interposed between the first and-second selectors, or atleast between the subscribers individual switches and the selectors. I

What I yclaiin as my invention is 1. In a telephone exchange system, anautomatic switch, a line running to said switch, a repeater in saidline, provided with relays forcontrolling the operation of saidautomatic switch, and a subscribers calling det vicefor transmittingelectrical impulses to operate said repeater, said automatic switchprovided with relays responsive to the. electrical impulses transmittedby the said,re-

peater relays, said repeater provided with parallel line circuitconductors each havinga normally open gap therein, and automatic meansfor closing said gaps simultaneously with the transmission of the lastimpulse necessary for completing connection between the telephone linesof the calling and called subscribers.

In a telephone exchange system, an automatic switch, a line-running tosaid switch, a repeater in said line, provided with a relay forcontrolling the operation ot said automatic switch, and a subscriberscalling dc rice tor transmitting electrit'ial impulses to operate saidrepeater, said automatic switch provided with a relay isponsire to theelectrirai impulses transmitted by the said repeater relay, saidretti-eater provided with pgeyallei line circuit conductors each haringa normally open gap therein, and automatic Vmeans for closing said gapssimultaneously with the transmission of the last impulsev necessary forcompletin connection between the telephone lines of t e calling andcalled subscribers. A

3. In a telephone exchange system, the combination of a trunk line, anautomatic switch at the end of said line, a repeater at the other end ofsaid trunk line, provided` with means for transmitting electrical im'pulses to said automatic switch, a plurality of telephone lines to whichthe said trunk line is common, a subscribers calling device for eachtelephone line, provided with mms for transmitting electricaliinpulsesto operate said repeater, automatic means-responsive to Said electricalimpulses, adapted for t connecting any calling telephone line with therepeater end of the trunk line, and a centra l source of current foroperating the said instrumentalities, said automatic switch providedwith electromagnetic means responsive to said electrical impulsestransmitted by Athe repeater, said repeater provided with combination ofaline circuit, a repeater in said circuit, adapted for repeating switchoperating electrical impulses from one section thereof to another, anautomatic switch adapted to receive the electrical impulses transmittedby said repeater, means for controlling or opera-ting said repeater, anda central. source of operating current, said circuit being provided witha normally open gap at the said repeater, and said repeater beingprovided with automatic means for closing` said gap after the operationof said automatic switch.

In a telephone exchange system, theconibination of a line circuit,automatic switches, a repeater in said circuit adapted 'for repeatingswitch operating electrical impulses from one section of said. circuitto another,

means for cont-rolling said repeater, and a `source of operatingcurrent.. said repeater provided with a rotary step-by-step switch'iiiechansin for controlling the continuity of said circuit. 4 i

(i. In a telephone exchange system, -the combination ot' a line circuit,a repeaterfin said line circuit, a source of eperatingcura rent` saidrepeater provided With line wipers,

'a roturjY magnet for operatingA said line wipers. and a rotary relayfor controlling the encigimngi ot said rotarymagnet, whereby the saidwipers are rotated one step each time the rotary relay is energized,

7. In a telephone exchange system, the combination of a line circuit, arepeater in said circuit,vadapted for repeating electrical impulses fromone section of said circuit to another, and a source of operatingcurrent, said repeater provided with a rotary step-by-step switchmechanism controlling the continuity of said circuit, a release-magnet,and a pair of line relays adapted to be energized simultaneously toenergize therelease-magnet and thereby ell'ect a release of the said"switch mechanism.

8. In a telephone system, a line, an iinpulse transmitter in said line,a repeater` associated with said line, a switchand a second lineextending from said repeater to said switch, said repeater' comprising'means responsive to the impulsesfrom said impulse transmitter forrepeating said impulses over the second line to operate said switch, andmeans for connecting said first and second lines after the switch isoperated.

9. AIn a telephone system, a line, an impulse transmitter in said line,a repeater associated with said line, a switch and a secondIinepermanently connecting said resaid -second 'line for operatin forArepeating impulses to the secondline for -operating said switch, andmeans for connecting said frstand second lines after the switchisoperated.

11.' In'a'J ytel-@phone system, a plurality of lines, means for sendinglimpulses over said lines,"a repeater, means for makin said repeateraccessible t0 any one of sai lines and for connecting said repeaterwithone of said lines, a switch and a line connecting said-'switch andrepeater, said repeater having means responsive to impulses from theconnected line for repeating the .impulses to said switch, and means forconnecting sai rst and second lines after the switch is operated.

12. In a telephone system, a plurality of lines, means for sendingimpulses over said lines, v'a repeater` means for making said repeaterlaccessible to anyone of said -lines and for connecting said repeaterwith one of said linesaa switch and a line connecting said switch andrepeater, said repeater having an electromagnetic impulse repeatingdevice responsive to the impulses transmitted over the connected linefor repeating impulses to said second line for operating said switch,and means for connecting said first and second lines after the switch isoperated.

13.*In a telephone system, a line, lan iinpulse transmitter in saidline,a repeater as-' sociated with said line, a switch and a second lineextending from said repeater to said switch, said repeater comprisingmeans responsive to the -impulses from said impulse transmitter forrepeating said impulses over the second line to operate said switch, andprogressively movable means for connecting' said first and second linesafter theswitch is operated.

' 14. In a telephone system, a line, an impulse transmitter in saidline, a repeater associated with said line, a switch and a sec ond lineplermanently connecting said. repeater wit said switch, said repeater'coin'-l prising means responsive to the impulses from said impulsetransmitter'for repeating said impulses over the second line to operatesaid switch, and progressively' movable means for connecting 'said rstand second lines after the switch is operated.

15. In atelephone' system, a line, an 'im- I pulse sender associatedwith said line, a repeater associated. with said line, another lineassociated with said repeater, a switch associated with said secondline, said repeater having an electromagnetic impulse repeating deviceresponsive'to the impulse sender for repeating impulses to the secondline for operating said switch, and progressively movable means forconnecting said first and second lines after the switch is operated.

1.6.- In a telephone system, a plurality oiY lines, means for sendinglimpulses over said lines, a repeater, means for making said repeateraccessible to any one of said lines and for connecting said repeaterwith one of said lines, a switch and ,a lin'e connecting said switch andrepeater said repeater having l means responsive to impulses Afrom theconnected 1ine-for repeating the impulses to said second linefor-operating said switch, and progressively movable means for connectngsaid rst and second lines after the switch is operated.'

l17. In a telephone system,a plurality vof lines, means for sendingimpulses'over said lines, a repeater, means for making said" re, Apeateraccessible to any one of said lines and for connecting said repeaterwith,` one of said lines, al switch and aline connectingy said switchand repeater', said repeater having an electromagnetic impulserepeatingl device responsive to the'impulse transmitted over said secondline for operatingsai switch, and progressively movable means forconnesting said first and second lines after the switch is operated.`

izo

v the connected line for repeating im ulses tov 18. In a telephonesystem, a line, an impulse transmitter in sai line, a repeaterassociated with said line, a switch and a second line extending fromsaid repeater to said switch, said repeater comprising means re*sponsive to the'impulses from said impulse transmitter for repeatingsaid impulses over lili the second line to operate said. switch, meansfor connecting said rst and second lines after the switch is.operated,and means for disconnecting the first and steond lines.

19. In a telephone system, a line, an impulse transmitter in said line,a repeater associated with said line, a switch and a second linepermanently connectingsaid repeater with said switch, said repeaterconiprising means responsive to' the impulses from said impulsetransmitter for repeat` ing' said impulses over the second line4 tooperate said switch, means ,for connecting' said first and second linesafter the switch is o erated,rand means for disconnecting the irst andsecond lines.

20. In a telephone system, a line, an im.4 pulse sender associated withsaid line, a repeater associated with said line, another line associatedwith said repeater, a switch associated with said second line saidrepeater having an electromagnetic impulse repeati'ng devi-ce responsiveto the impulse sender for repeating impulses to the second line foroperating said switch,` means for connecting said first andvsecond linesafter the "switch iso erated, and means for disconnecting the rst andsecond lines.

21. In a telephone system, a plurality of lines, means. for sendingimpulses over said lines, a repeater, means fr making said repeateraccessible to any one of said lines and for connecting said repeaterwith one of said lines, a switch and a line connecting said switch andrepeater, said repeater having means responsive to impulses from theconnected line for repeating the imp ulses to said second line foroperating said switch, means for connecting` said first. and secondlilies after the switch is operated, and means for disconnecting thefirst and second lines.

22. In a telephone system, a plurality of lines, means for sendingimpulses over said lines, a repeater, means for making said repeateraccessible to anyone of said lines and for connecting said repeater withone of said lines, a switch and a line connecting said switch andrepeater, said repeater having an electromagnetic impulse repeatingdevice responsive to the impulses transmitted over the connected linefor repeating impulses to said second line for operating said switch,means for connecting said first andsecond lines after the switch isoperated` and means for disconnecting the lirst and second lines.

In a telephone system` a linenn impulse transmitter in said line, arepeater ,associated with said line.s a switch 'and e secondlineextending from said repeater to said switch, said repeater comprisingmeans responsive to the impulses from saidiinpulse transmitter .forrepeating` said impulses over the second line to operate said switch,means for connecting said first and second lilies after the switch isoperated, and means *for releasing said switch con;- trolled by saidrepeater. A

2l. In a telephone system, a line, an impulse transmitter in said line,-a repeater associated with said line, a switch and a second line'permanently connecting said repeater with said switch, said repeatercomprising means responsive to the impulses from said impulsetransmitter for repeating said impulses over the second line to operatevsaid switch, means for connecting said first. and second lines after theswitch is operated, and means for releasing said switch controlled byVsaid repeater.

25. In a telephonesystem, a line, an impulse sender associated with saidline, a repeaterassocia-ted with said line, another line associated withsaid repeater, a switch associated with said second line, said repeaterhaving an electromagnetic impulse repeating deviceresponsive totheimpulse sender for repeating impulses to the second line for op- Ycrating saidswitch, means for' connectinr said first and `second linesafter the switc is operated, and means Yfor releasing said switchcontrolled hy said repeater.

2G. In a telephone system, a'plurality of lines, means f or sendingimpulses' over said lines, a repeater, means 'for making said repeateraccessible to any one of said lines and for connecting said repeaterwith one of said lines, a switch and a line connecting said switch andrepeater, said repeater har-` ing means responsive to impe/lees fromthi* connected line for repeating the impulses to said second line forope ating said switch, means tor connecting said' first and second linesafter the switch is operated. and means for releasing Isaid switchcontrolled by said repeater. f

27. In a telephone lines, means for sending impulses over said lines,arepeater, means for mak-ing` said re-Y peater accessible to any one' ofsaid lilies and for connecting said `repeater with one of saidlines. aswitch and a line connecting` said switch and repeater, said repeaterhaving-.im electromagnetic impulsel rcpeutingde. vice responsive to theimpulses transmitted over the connected line for repeating im pulses tosaid second line for operating said switch, means4 forconueciingl saidtirst and 4 second lines afleithe switch is operated, and `means forreleasing' sind switch controlled by said repeater.

In a telephone s ymteni` a iin@s an Viin-- pulse transmitter in saidline. a repeater associated with said line, a switclrand a vL.

system, a plurality ofcontrolledby said repeater, and means forreleasing said progressively movable means f io iii-connect the firstand second lines.

2S). In a telephone system, .a line, an impulse transmitter in saidline, a repeater associated with said line, a switch and a second linepermanently connecting said repeater 'with said switch, said repeatercomprising iiiea'ns responsive to the impulses .trom said impulsetransmitter for repeating .said impulses over the second line to operate.said switch, progressively movable means il'oi' connecting said firstand second lines after the switch is operated, means forli-eleasing saidswitch controlled by s aid repeater, and i'iieans for releasing saidprogressively movable means to disconnect the 1li-.st and second lines.

30. In a telephone system, aline, an iinpiilsc sender associated withsaid line, a repeatei associated with said line, another vlineassociated with said repeater, a switch associated with said secondline, said repeater having an electromagnetic impulse repeating deviceresponsive to the impulse sender for repeating .iin )ulscs to the secondline for operating sai switch, progressively movable means forconnecting said first and second lines after the switch is operated,means for releasing said switch controlled by said repeater, and meansfor releasing said progressively movable means to disconnect the firstand second lines.

3l. In a telephone system, a plurality ot lines` meanstor sendingimpulses over said lines, a repeater, means Jfor makingr said repeaieracccrsililr to any one oi" said lines and for connecting .said repeaterwith one of said lilies, a switch and a line connecting said switch andrepeater, said repeater having means responsive to impulses from theconnected line tor repeating `the impulses to said t vsecond vline foroperating said switch, progressively movable means for connect-ing saidfirst. and second lines after the switch is opi-irated, means forreleasing Said switch controlled by said repeater, and means fori'eleasiiig-said progressively movable means to disconnect the first andsecond lines.

2&2, ln :i telephone ski'steni. a plurality of lines. means t'or sendingimpulses over said lines, a repeater. ii'ieans 'for making said repeatcraccessible to any one of said lines and for connecting said repeaterwith one ol' said lines, a switch and a line connecting said switch andrepeater, .said repeater having :in electioiiiagiivtic impulse repeatingdevice responsive to the impulses transmitted over the connected linefor repeating im lsesV to said second line for'operating sai switch,

progressively movable means for connecting said first and second linesafter the switch is operated, means for releasing said switch.controlled by said repeater, and means lfor releasing said progressivelymovable means to disconnect the first and second lines.

33. In a telephone system, a telephone line, means `for sending impulsesover said line, a repeater, means for connecting said line with saidrepeater, a switch, a line eX- tending from said repeater to saidswitch, another switch, electromagnetic means in said repeaterresponsive to said-impulses for operatin said switches to build `a lineconnection rom the repeater to a second telephone line and -to signalsaid second telephone line, and means in said repeater for connectingthe first line with the switch line after the first switch is operatedwhereby a connection is established between the first. line and thesecond line.

34. In a telephone system, a telephone line, means for sending impulsesover said line, a repeater, means for connecting said line with saidrepeater, a. switch, aline extending from said repeater to said switch,another switch, electromagnetic means' in said repeater responsive tosaid impulses for operatin said switches to build a line connection,.rom the repeater. to a second telephone line and to signal said secondtelephone line, and progressively tmovable means in 100 said repeaterfor connecting the first line with the switch line afterthe first switchis operated whereby a connection is established between the first lineand the second line.

35. In a telephone system, a telephoneline, 105 means for sendingimpulses over said liner, a repeater, means for connecting said linewith said repeater, a switch, a line extending from said repeater tosaid switch, another switch, electromagnetic means in said re 110 peatcrresponsive to said impulses for operating said switches to build a lineconnection from the repeater to a second telephone line and to signalsaid second telephone line, means in said repeater for connecting the115' first line with the switch line after the first switch is operatedwhereby a connection is established' between the first line and the sec`ond line, and means for releasing said siiltitches controlled by saidrepeater.

i36. Iii atelephone system, a telephone line, iiieaus for sendingimpulses over said line, a repeater. means' for connecting said linewith said repeater, a switch, a line extending from said repeater tosaid switch. another switch, 125 electroniagiictic iiieaiis inSaidrepeater responsive to said impulses for operating said switches tobuild a line connection from the rcpeatcijto a second telephone line andto signal said second telephone line, progres- 130 sively movable meansin said repeater for connecting the first line with the switch lineafterthe first switch is operated whereb a connection is established betweentheV rst line and the second line, and means for re- 'sponsiveto saidimpulses for operating said switches to build a line connection from therepeater to a second telephone` line and to signal said second telephoneline, means in said repeater for connecting the first line with theswitch line after the first switch is operated whereby a connection isestablished between the first line andthe second line, means forreleasing said switches controlled by said repeater, and releasing meansfor disconnecting the first line from the said first switch.

38. In a telephone system, a telephone line, means for sending impulsesover said line, a repeater, means for connecting said line with saidrepeater, a switch, a line extending from said repeater to said switch,another switch, electromagnetic means in said repeater responsive tosaid impulses for operating said switches to build a line connectionfrom the repeater to a second telephone line and to signal said secondtelephoneline, progressively movable means in said repeater forconnecting the first line with the switch line after the first switchis-opcrated whereby7 a connection is established between the first lineand the second line, means for releasing said switches controlled bysaid repeater, and` releasing' means for disconnecting the first linefrom said first switch. f

39. In a telephone system, a telephone line, means for sending impulsesover said line, a repeater, means 'for connecting said i line withsaidrepeater, a switch, asline connecting said switch with said repeaterand means in said repeater responsive to said impulses for operatingsaid switch, and means for connecting said telephone line with saidswitch line after the switch is operated, releasing mechanisms in saidswitch and in said last means and circuits flor operating liu-.saidmechanisms from said repeater in response to said impulse sending means.

l0. In a telephone system, a telephoneline, means for sending impulsesover said line, a' repeater, means for connecting said line with saidrepeater, a switch, a line extending from said repeat-cr to said switch,another switch, electromagnetic means yin said repeater responsive losaid impulses. for operatingsaid swiichcs to lmilfl a line connectionfrom the repeater lo a second telephone line and to signal said vsecondtelephone line land means in said repeater for connecting inductivelythe/first line with the switch line after the first switch is operatedwhereby a connection is established between the first line and thesecond line.

41. In a tele hone system, a telephone line, means .for sen ing impulsesover said line, a repeater, means for connecting said line with saidrepeater, a switch, a line extending from said repeater to said switch,another switch, electromagneticy means in said repeater responsive tosaid impulses for operating said switches to build a line connectionfrom the repeater to a second telephone line and to signal said secondtelephone line, and progressively movable means in said repeater forconnecting inductively the first line with the switch line after thefirst switch is operated whereby a connection is established between thefirst line and the second line.

42. In a telephone system, a telephone line, means for sending impulsesover said line, a repeater means for connecting said 'line with saidrepeater, a switch, a line extending from said repeater to said switch,another switch, electromagnetic means in said repeater responsive tosaid impulses for operating said switches to build a line connectionfrom the repeater to a second telephone line and to signal said secondtelephone line, means in said repeater for connecting indnctively thefirst line with the su tch line after the first switch is operatedwhereby a connection is established 'between the first line and thesecond line, and means for releasing said switches controlled by saidrepeater.

i3. In a telephonesystem, a telephone line, means for sending impulsesover said l ine, a repeater, means for )connecting said line withsaid'repeatcr, a switch, a. line extending from said repeater to saidswitch, another switch, electromagnetic means in said repeaterresponsive to said impulses for hpnl-ating said switchesl to build aline-con` nection from lhc repeater to a second telcphone linc aml tosignal said second telephone line, progressively mor-able means in saidrepeater for connecting inductivcly the firstline with the switch lineafterl the first switch is operated whereby a connection is establishedbetween the first line and the second line, and means for releasing saidswitches controlled -by'said repeater.

In a telephone,system, a telephone line` means for sending impulses oversaid line..a repeater. means for connocling said line with saidrepeater. a switch` a line cx lcmlimcr from said repeater to ysaidswitch, anoi'hcrswitch, clcctromagnelic means in said repeaterresponsive to said impulses for operating said switches to build a linecounecliim from the repeater lo a second telephone line and io signalsaid set-nul lele phone line, means in said rcpeateij :for connectinginductively the first line with the switch line after the first switchis operated whereby a connection is established between 4the first lineand the second line, means for releasing said switches controlled bysaid repeater, and releasing means for disconnecting the first line fromthe said first switch.

In a telephone system, a telephone line, means for sending impulses oversaid line, a repeater, means for connecting said line with saidrepeater, a switch, a line extciidingfrom said repeater to said switch,another switch, electromagnetic means in said repeater responsive tosaid impulses for operating said switches to build a line con` nectionvfrom the repeater to a second tele` phone line and to signal saidsecond telephone. line, progressively movable means in 'said repeaterfor connecting inductively the first line with the switch line after thefirst switch operated whereby a connection is established between thefirst line and the second line, means for releasing said switchescontrolled by said repeaterand releasing means for disconi'iecting thefirst line vfrom said first switch.

16. In a telephone exchange system, the combination of one exchange,another eX- change, a trunk line connecting the two eX- changes, anautomatic switching machine at. one end of said trunk liiie, a pair ofrelays at the other end of said trunk line', means by which theenergizing of' said relaysI severs the trunk line, and means by which acalling subscriber employs saidA relays for controlling said auton'iaticswitching machine.

47. In a telephone exchange system, the combination of a trunk line, anautomatic switchv at one end of said trunk line, a pair of relays at theotlit" end if said trunk line, means by which the trunk line is severedby the energizing of said relays, and means by which a callingsubscriber employs said relays tor controlling said automatic switch.

48. ln a telephone exc hange"systein, a. first-selector, means thereinhaving one ino tion to select groups and another motionA to connectwith'a line in any selected group, a second-selector, a trunk linevconnecting the first-selector with the second-selector, a repeaterprovided with relays controlling the continuity of the trunk lineconnection bei tween the two selectors, a calling subscribcrs tor, acalling device by which the subscriber controls the first-selector, bywhich the second-selector is controlled through the ine-- dium of therepeater relays, a source of operating current, said repeater relaysprovided with normally open contacts anda ground connection forgrounding the trunk line. when the relays are energized.

4a9. In a telephone exchange system, the combination of one exchange,another exchange, a trunli line connecting the two eX- changes, anautomatic switching machine at one end of said trunk line, means thereinhaving one motion to select groups and anf other motion to connect witha line inany selected group, a pair of relays at the other end of saidtrunk line, means by which the energizing of said relays sevcrs thetrunk line, and means by which a calling subscriber employs said relaysfor controlling said automatic switching machine.

50. In a telephone exchange system, the combination of a trunk line, anautomatic switch at one end of said trunk line, means therein having onemotion to select groups and another motion to connect-with a line in anyselected group, a pair of relays at the other end of said trunk line,means by which the trunk line is severed by the en ergizing of saidrelays, and means by which a calling subscriber employs said relays forcontrolling said automatic switch.

5l. An. automatic telephone system coniprising a plurality ofelectrically-propelled step-b'y-step switches, a calling subscribersline having a calling device, said line teinporarily connected with acalled subscribers line through the. i'nedium of said switches, thelatter controlled and operated through the' medium of' said callingdevice at the calling subscriber-s station, said switches including apair of line-relays adapted to remain bridged across the talking circuittemporarily establishedfor carrying on con versation'between the twosubscribers, and also including a pair of repeating relays which remainbridged across the said'tallo ing-circuitand through the medium of whichthe calling impulses transmitted by the calling subscriber are repeatedin the windings of the said ,first-mentioned relays, means operated bybattery current and under the control of any calling subscriber foradmitting alternating current onto any called subscribers lineandthereby producing an audible signal at the latters station` 52. Anautomatic telephone system comprising a plurality of electricallyropelled step-by-step switches, a calling su scribers' line having acalling device, said line temporarily connected with a calledsubscribers line through themediuin of said switches, the lattercontrolled and operated through the mediurnof said calling device at thecalltelephone line connected with said first-solco;l

ing subscribers station, a pair of line-relays" adapted to remainbridged across .the

-talking-circuit .temporarily established for carrying on conversationbetween the two subscribers, and also 'including a pair of repeatingrelays which remain bridged across the said talkin circuit and throughthe medium of which the calling'inipulses transmitted by the callingsubscriber are repeated in the windings of the said first mentionedrelays, and means whereby a subscriber may -a condenser in sai image1momentarily establish the live or charged ound circuits necessary incalling the numgdr of another subscriber.

53. An automatic telephone system comprising a plurality1 ofelectrically popelled step-by-step switc cs,'a calling su criberslinehaving a calling device, said line temporarily connected with a calledsubscribers line through the medium of the said switches, the, lattercontrolled and operated through the medium of said calling device `atthe callin subscribers station, said switches inclu in a pair ofline-relays adapted to remain iidged across the talking prisng aplurality1 of electrically i ropelled step-by-step switc es, a cal1ingsu .scribers line having a calling device, said line tem-'rarily'connected with a called subscribers liietliiough 4the medium ofsaid switches, the latter .controlled and operated through the medium ofsaid calling .device at t e calling subscribers station, said switchesincluding a air of llnefrelays adapted to remain bridgedA across thetalking circuit temporarily established for carryin on convel-,sationbetween .the two subscri ers, and also includin a pair of Arepleatingrelays which remainrdged across-'t esai talking circuit and through themedium 'of Whic the calling impulses. transmitted by the call- 1nsubscriber are repeated in the 4windings Ofgthe lsaid first mentionedrelays, and means whereby a called subscriber may momentarilyyestablish'the live .or char ed ground cil-cuits necessary in automat1ca1eiecting a disconnection between subscri ers lines after theconversation is terminated,

l 55. In a tele hone exchange system sub# stantially is disclosed, thecombination of a connector provged with a line-conductor,

line-conductor, a switchwiper in said line-conductor, a bank oflinecontacts a adapted to be engaged by said switch-wiper, a singlenormallympen switchpoint in the line-conductor between said condenserand switch-wiper, said wiper normallv insulated from battery and ground,and subscribers impulse transmitters er cailing devices ier transmittingto the exchange or central station the electrical impulses representing'the number of any called sub- Scriber.x y A 56. An automatic telephonesystem comprising a pluralit of electrically propelled stepbyst`ep switces, a calling su scribers line having a callingV device, said linetemoi'arily connected with a called subscribers ine through the mediumof said switches, the latter controlled and operated throu li the mediumof said callin' device'at t e calling subscribers station, t e apparatusas a Whole including a pair O f line-relays ladapted Ito remain bridgedacross the talking-circuit temporarily egtablished for carrying onconversation between the two subscribers, and also including a pair ofrepeating-relays which remain bridged across the said talking circuitand through the medium of which theicalling impulses transmitted by thecalling subscriber are repeated in the windings of said rsbnentionedrelays.

57. In a telephone system, a trunk line, a

pair of condensers therein, a pair of relays permanently bridged acrossthe trunk line at one side of said condensers, a batter having one polepermanently connected to t e bridge at a point between said rela s, asecond pair of relays, another battery avin one pole normally connectedwithboth si es of said trunk line through the medium of the second pairofrelays, each battery having its other pole grounded, and means forgroundin the runk line by the energizing of said rstmentioned pair ofrelays, to energize the said last-mentioned pair of relays, the saidlast-v mentloned pair of relays bein bridged across the trunk line atthe other side of said condensers, said trunk line havingcontinuousparalel sides. Y

5B. In a telephone system, a trunk line, a condenser in each side ofsaid trunk line, a

relay permanently bridged acrossthe trunk linev at one side of saidcondensers, another relay permanently Vbridged across the trunk line atthe other side of said condensers,v and means by which the 'energizingof the first- Vmentioned relay causes the energizing of the saidlast-mentioned `relay, said trunk `line havin continuous parallel sides.a

59. n a telephone system, a trunkline having continuous parallel sides,a condenser in each side of, said trunk line, one or more relayspermanently bridged across the trunk line lat; one side of saidcondenseis, one or more' relays responsive to said rst-mentioned relays,connected with the trunk line :it the other sideof said condensers, and

`switching meanscontrolled over the trunk line by said last-mentionedrelays. i

60. ln telephone, system, a trunk line having continuous parallel sides,rc1-active connections in said trunk line, one or more relayspermanently bridged across the trunk line 'at one side of said re-activeconnections,

